X-ray computed microtomography and the identification of wood taxa selected for archaeological artefact manufacture: Rare examples from Australian contexts

Wooden artefacts are seldom recovered from Australian archaeological contexts, limiting our understanding of an important component of past Indigenous socio-economic systems. When recovered, the taxa used for construction are very rarely identified, and when undertaken, taxonomic identifications are generally unsubstantiated. For wood taxa to be identified, the microscopic elements of the xylem structure need to be observed and described from three planes. Conventional microscopy methods require physical sectioning, which is a complex, time-consuming process, whereas X-ray computed microtomography is non-invasive and expeditious. Here we describe the use of X-ray microtomography to identify the material of two wooden implements, the negative component of a fire drill and an artefact fragment, both recovered from Riwi cave in the southern Kimberley of Western Australia. By drawing on archaeobotanical analyses conducted at Riwi cave (wood charcoal and other macrobotanical remains), we are able to illustrate that the past inhabitants of Riwi selected certain woods for specific purposes within the last 1000 years of occupation at the site.